Fluid pressure operated boosters



June 11, 1968 Original Filed Nov. 21, 1963 A. J. WILSON FLUID PRESSUREOPERATED BOOSTERS 2 Sheets-Sheet l June 11, 1968 A. .1. WILSON 3,337,540

FLUID PRESSURE OPERATED BOOSTERS Original Filed Nov. 21, 1963 2Sheets-Sheet 23 United States Patent Office 3,387,54fi Patented June 11,1968 3,387,540 FLUID PRESSURE UPERATED BOUTERS Alexander J. Wilson,Warwickshire, England, assignor t Girling Limited, Tyseley, England, aBritish company Original application Nov. 21, 1963, Ser. No. 325,227.Divided and this application Sept. 15, 1966, Ser. No. 579,542 Claimspriority, application Great Britain, Nov. 21, 1962, 43,985/ 62 12Claims. (Cl. 91-369) ABSTRACT 0F THE DISCLOSURE In a pedal controlledvacuum booster particularly for braking systems, a deformable annularflexible plate abutting the pressure diaphragm and being adapted to dishto provide a reaction or feel" on the pedal operated control valve.Though the plate can be of any construction whereby it deforms or dishesto provide feel, one preferred construction is a diaphragm like platehaving a series of radially directed flutes on its forward face adaptedto abut against an annular abutment ring carried by the output memberwhereby the central part of the plate is moved rearwardly against thecontrol valve.

This application is a division of application Ser. No. 325,227 filedNov. 21, 1963.

This invention relates to improvements in fluid-pressure operatedboosters of the kind in which power is generated by the application ofdifferential fluid pressures to opposite sides of a movable wall underthe control of a mechanically operated valve.

In systems employing boosters of this kind, and particularly in brakingsystems for vehicles where the valve is manually controlled, it isdesirable that there should be a reaction on the valve operating rod orthe like proportional to or dependent upon the differential pressures onopposite sides of the wall so that the operator is given the feel of thebrakes and can more readily regulate their application.

According to one feature of my invention, in a fluidpressure operatedbooster incorporating a control valve mechanism and a movable wall, themovable Wall dishes or is deformed conically by differential pressurewhen the booster is energized, the dishing or deformation provide areaction on the control valve dependent upon the differential pressures.

According to a further feature of my invention, in a fluid pressureoperated booster incorporating a control valve mechanism and a movablewall, the control valve mechanism is received within the hollow stem ofa generally mushroom shaped transmission member passing through the walland the forward face of the wall abuts against one end of thetransmission member to move it forward when the booster is energized,and the rear face of the wall abuts at a position radially inwards ofthe abutment with the transmission member against a reaction componentslidable upon the stem, the wall dishing or deforming comically bydifferential pressure and the dishing or deformation provides a reactionon the control valve mechanism which is dependent upon the differentialpressure.

The wall is provided with a central opening and the control valve isconnected to the inner edge of the wall adjacent the opening.

The wall is conveniently provided by a flexible piston, or alternativelya diaphragm, which preferably is stiffened by a flexible ring securedthereto, and which may have a series of radially directed flutes on itsforward face adapted to abut against an annular abutment ring on thehead, the rear face of the wall providing the abutment with the reactioncomponent.

Alternatively the head may have adjacent its periphery a series ofcircumferentially spaced abutments against which the portions of thedisc between the flutes are adapted to bear.

A practical form of fluid-pressure operated booster embodying myinvention is illustrated in the accompanying drawings in which:

FIGURE 1 is a longitudinal section through a booster; and

FIGURE 2 is an isometric view of a deformable wall incorporated in thebooster shown in FIGURE 1;

In the booster illustrated in FIGURE 1, 10 is a housing or cylinder ofthe booster which is divided by a dia phragm 11 into front and rearchambers 12 and 13 respectively. The forward chamber 12 is connected tothe inlet manifold or other source of vacuum by a connection 14 housinga non-return valve and mounted on the front wall 15 of the cylinder andthe rear chamber is also connected to vacuum through valve meanscontrolling passages in a valve mechanism for the booster.

The valve mechanism comprises a pair of concentric sleeves 16 and 17 ofwhich the inner sleeve 16 is slidably mounted in the outer sleeve 17 andis generally of mushroom shape having on its forward end a head 18 ofsubstantial diameter. The rear chamber 13 is normally in communicationwith vacuum through a port 19 in the wall of outer sleeve co-operatingwith a radial port 20 in the wall of the inner sleeve which leads into ablind bore 21 in which works an axially movable valve spool 22, theblind bore 21 communicating with the forward chamber 12 through alongitudinal bore 23 in the inner sleeve.

Stem 24 of the valve spool 22 is urged by a compression spring 25 intoengagement at its rearward end with a forwardly extending axial portion26 of the outer sleeve which is recessed to receive an actuating rod 27.The outer sleeve 17 is resiliently biased in a rearward direction by acompression spring 28 engaging at one end with the axial portion 26 ofthe outer sleeve and at the other end with a cylindrical abutment member29 attached to a flexible rubber cylindrical boot like insert 30connected to the inner sleeve. The rear ends of the sleeves are enclosedby a boot 31 through which the actuating rod extends and which is incommunication with atmosphere through a passage 32 and an air filter 33.

The diaphragm 11 is clamped at its outer edge to the periphery of thehousing or cylinder 10 and is secured at its inner edge to the outersleeve 17. In front of the diaphragm there is a centrally aperturedresilient or flexible sheet metal or other disc 34 (FIGURE 2) which isformed with a series of angularly spaced flutes 35 of which the axialdepth tapers from a maximum at the centre to a minimum or zero at theperiphery of the disc, the flutes being directed forwardly. The rearface of the disc is engaged by the diaphragm 11 over the outer part ofits area, the flutes 35 bear at intermediate points in their lengths ona rearwardly facing annular abutment 36 on the head 18 of the innersleeve 16, and the inner edge of the disc engages a forwardly facingannular shoulder 37 on the outer sleeve.

Normally both chambers 12 and 13 are in communication with a source ofvacuum as described above, the diaphragm being balanced and held inposition by a return spring 38. The spool valve 19 is resiliently urgedinto engagement with the forward face 39 of the rubber insert 30 toprevent atmospheric air from entering the rear chamber 13.

When the actuating rod is operated it moves the outer sleeve 17forwardly to apply a forwardly directed force to the inner edge of thefluted disc 34 and at the same time it advances the valve spool 22 untilthe front face 39 of the rubber insert 39 engages an annular seating 40in the inner sleeve 16 adjacent the bore 21 in which the valve spoolworks and which isolates the rear chamber of the booster by cutting offthe vacuum supply through passage 23 in the inner sleeve 16.

Further movement of the actuating rod moves the valve spool away fromengagement with the forward face 39 of the rubber insert to allow air topass through the inner sleeve past the valve spool and through passages26 and 29 in the sleeves and enter the rear chamber 13 to act on thediaphragm. As the diaphragm moves forwardly it takes with it the outersleeve 17 which actuates the piston of the master cylinder through a rod41 and the head 18 of the inner sleeve and at the same time it tilts theouter portion of the disc relative to the head and levers formed by theflutes 35 are tilted about their abutment 36 on the head and apply arearwardly directed force to the outer sleeve by the engagement of theinner edge of the disc with the annular shoulder 37, this force beingtransmitted to the actuating rod 27 and hence to the operators foot.

In another arrangement the annular abutment is replaced by separatecircumferentially spaced abutments against which the portions of thedisc between the flutes are adapted to bear.

In the event of failure of the booster the valve spool 22 is arranged toengage the inner sleeve at the forward end of the blind bore 21 so thatthe effort applied to the actuating rod can be transmitted mechanicallythrough the two sleeves and the valve spool to the piston of the mastercylinder to apply the brakes.

What is claimed is:

1. A fluid-pressure operated booster comprising a housing defining apower chamber, at least one pressure responsive wall movable in saidhousing and adapted to be subjected to differential fluid pressure whenthe booster is energized, said movable wall having aforward face and arear face, an operating member, a force transmitting member, abutmentmeans associated with said force transmitting member and engageable withsaid forward face of said movable wall to provide a fulcrum, meansassociated with said operating member co-operating with said rear faceof said movable wall and adapted to abut said wall at a point spacedradially inward from said fulcrum, whereby upon energization of saidbooster said movable wall tilts about said fulcrum and applies to saidoperating member a reaction dependent upon the differential pressure towhich said movable wall is subjected.

2. A fluid-pressure operated servo-motor comprising a housing defining apower chamber, a deformable pressure responsive wall movable within saidhousing and adapted to be subjected to differential fluid pressure whenthe servo-motor is energized, said movable wall having a forward faceand a rear face, a first chamber on one side of said wall, a secondchamber on the other side of said wall, an operating member within saidfirst chamber, a force transmitting member within said second chamber,abutment means associated with said force transmitting member andadapted to engage an annulus on said forward face of said deformableWall spaced radially inward of a radius of said movable wall includingits centre of pressure, said abutment means providing a fulcrum aboutwhich said wall deforms when the servo-motor is energized, and meansassociated with said operating member in abutment with said wall on anannulus spaced radially inward of said fulcrum whereby upon energizationof said servo-motor said movable wall deforms about said fulcrum toproduce a reaction on said operating member in proportion to the degreeof energization.

3. A fluid-pressure operated booster comprising a housing defining apower chamber, a pressure responsive movable wall in said housing havinga forward face and a rear face and adapted to be subjected todifferential fluid pressure when said booster is energized, manualopcrating means co-operating with said rear face of said movable wall,pressure differential control means actuated upon operation of saidmanual operating means to affect movement of said movable wall, forcetransmitting member movable by said wall, abutment means on said forcetransmitting member engaging said forward face of said wall at aposition radially inwards of the effective centre of pressuredifferential on the wall, and providing a fulcrum for said wall, wherebyupon energization of said booster said movable wall pivots about saidfulcrum to apply to said manual operating means a reaction proportionedto the differential pressure to which said movable wall is subjected.

4. A fluid-pressure operated booster as claimed in claim 3, wherein saidmanual operating means cooperates directly with said rear face of saidmovable Wall, and said wall is movable solely by said manual operatingmeans upon failure of said pressure differential control means.

5. A fluid-pressure operated booster as claimed in claim 3, wherein saidmanual operating means co-operates with said rear face of said movablewall at a position radially inwards of the position at which saidabutment on said force transmitting means engages said forward face ofsaid movable wall.

6. A fluid-pressure operated booster as claimed in claim 3, wherein saidmanual operating means and said force transmitting means are normallyrelatively movable to actuate said pressure differential control means,and are movable in unison upon failure of said control means.

7. A fluid-pressure operated booster as claimed in claim 3, wherein saidmanual operating means and said force transmitting means are movable inunison upon failure of said control means Without force transmissionthrough said pressure differential control means.

3. In a fluid pressure motor mechanism, a motor having an expansiblechamber, a flexible diaphragm forming one Wall of said chamber, adistortable diaphragm plate supporting said diaphragm, valve meansadapted to direct fluid pressure from a source to said expansiblechamber and from said chamber, means engaging said diaphragm plate totransmit force from said diaphragm plate, said diaphragm plate beingadapted to distort in response to the fluid pressure in said expansiblechamber, and manually operable means to control said valve means, saiddiaphragm plate directly engaging said manually operable means wherebydistortion of said diaphragm plate opposes said manually operable meansto thereby tend to reduce the power of said motor mechamsm.

9. In a fluid pressure motor mechanism, a motor havmg an expansiblechamber, a flexible diaphragm forming one wall of said chamber, adistortable diaphragm plate adapted to support said diaphragm, andcontrol means including valve means for controlling communicatmg betweensaid expansible chamber and a source of fluid pressure and furtherincluding a manually operable unit, said diaphragm plate beingdistortable in response to fluid pressure in said expansible chamber andhaving a portion directly engaging said manually operable unit when thelatter operates said valve mechanism, whereby distortion of saiddiaphragm plate causes it to oppose movement of said manually operableunit and thereby tend to reduce the power of said motor mechanism.

10. A fluid pressure motor mechanism comprising a motor having anexpansible chamber, an annular flexible diaphragm forming one wall ofsaid chamber, an annular distortable diaphragm plate supporting saiddiaphragm, control means including a manually operable unit and controlvalve means partly carried by said manually operable unit forcontrolling communication between said expansible chamber and a sourceof fluid pressure, an axial body in which said manually operable unit isaxially movable, and means co-acting between said body and said plateintermediate the radially outer and inner limits of the latter forfulcrumming said plate whereby the outer portion of said plate is flexedin the direction of movement urged by pressure in said chamber while theradially inner portion of said plate tends to rock in the oppositedirection, said radially inner portion of said plate being directlyengageable with said manually operable unit to oppose valve-operatingmovement thereof to thereby tend to reduce the power of said motormechanism.

11. A fluid pressure motor mechanism comprising a motor having anexpansible chamber, a flexible diaphragm forming one wall of saidchamber, a distortable diaphragm plate member supporting said diaphragm,a rigid axial body member forming with said diaphragm and with saidplate member a pressure-responsive unit for said motor, one of saidmembers having rib means engageable by the other of said members andforming fulcrum means for said plate member whereby the admission ofpressure to said chamber moves the radially outer portion of said platemember and said diaphragm in one direction and rocks the inner portionof said plate member in the opposite direction, said rib means beingarranged closer to the radially inner limit of said diaphragm than tothe radially outer limit whereby pressure acting against the radiallyouter portion of said diaphragm produces a moment about said fulcrummeans greater than the moment acting in said opposite direction radiallyinwardly of said fulcrum means, and control means including a manuallyoperable unit and valve means partly carried thereby for supplyingpressure to said chamber upon operation of said manually operable unit,the radially inner portion of said plate member being engageable withsaid manually operable unit upon the fulcrumming of said plate member tooppose valve operating movement of said manually operable unit.

12. A motor mechanism according to claim 11 wherein said plate isannular and has its surface continuity disturbed to vary the normalstillness thereof to determine its resistance to distortion and thusvary the pressure in said chamber necessary to engage the radially innerportion of said plate with said manually operable unit and opposemovement of the latter.

References Cited UNITED STATES PATENTS 3,183,789 5/1965 Stelzer 91-369PAUL E. MASLOUSKY, Primary Examiner.

